Language impaired (LI) children have been shown to demonstrate significant deficits in processing both nonverbal as well as verbal stimuli which incorporate rapidly changing acoustic cues. Processing stimuli which incorporate rapidly changing sequential information has been shown to be specialized to the left hemisphere in human as well as animal subjects. Recently, in vivo, brain imaging studies have implicated aberrant structural cerebral asymmetry in LI children. However, the etiology of these deviations in both functional and structural lateralization is unknown. Studies with animal subjects have shown a relationship between gender, hormonal manipulation and perinatal stress on the development of structural cerebral lateralization. However, the relationship between structural and functional lateralization, specifically for auditory sequential processing, has not been studied. The specific aims of the proposed pilot studies are to investigate the role of gender, hormone manipulation and perinatal stress on the development of both functional and structural cerebral lateralization. We propose to use a recently developed dichotic listening paradigm to study functional hemispheric specialization for auditory temporal processing in rats. Next, we will investigate the effects of gender, hormone manipulation and perinatal stress on 1) functional lateralization of temporal auditory processing and 2) structural cerebral lateralization as measured by the size of the corpus callosum and cortical thickness asymmetry. The long-term objective of these pilot studies is to bring together animal and human studies which investigate factors influencing the development of cerebral asymmetry, in order to better understand the relationship between structural and functional cerebral lateralization. Although we have focused on cerebral lateralization issues in this proposal, we recognize the high-risk of relating the results of lateralization studies in lower animals to humans. It should be emphasized that an additional purpose of this proposal is to bring together scientists with very different areas of expertise in order to determine the feasibility of developing an animal model for studying the neural basis of auditory temporal processing. Given the striking deficits in temporal processing that have been demonstrated in language impaired children, the development of an animal model would potentially provide a much needed venue for studying the neurobiological basis of these disorders.